US2530614A - Transmitter and receiver for single-sideband signals - Google Patents

Transmitter and receiver for single-sideband signals Download PDF

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Publication number
US2530614A
US2530614A US685122A US68512246A US2530614A US 2530614 A US2530614 A US 2530614A US 685122 A US685122 A US 685122A US 68512246 A US68512246 A US 68512246A US 2530614 A US2530614 A US 2530614A
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frequency
oscillations
auxiliary
oscillation
oscillator
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US685122A
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Hugenholtz Eduard Herman
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/10—Ion sources; Ion guns
    • H01J49/12—Ion sources; Ion guns using an arc discharge, e.g. of the duoplasmatron type
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers
    • H04B1/302—Circuits for homodyne or synchrodyne receivers for single sideband receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/68—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for wholly or partially suppressing the carrier or one side band

Definitions

  • This invention relates to atransmitter for the transmission of one-sideband signals with suppressed carrier wave and for the simultaneous transmission of one or more, preferably two, auxiliary oscillations and to a receiver for the reception of such one-sideban'd signals.
  • auxiliary oscillations are, as a rule, transmitted simultaneously with the signal, for the carrier wave to be utilized for the detection must be locally generated in the receiver, so that particu lar steps have to be taken to prevent that any change of the frequency of the (suppressed) carrier wave in the transmitter or of the locally generated carrier wave in the receiver has a harmful influence on the satisfactory reception of the signal or even makes such a reception quite impossible.
  • the invention provides means with which the complete or substantially complete synchronism of the locally generated carrier wave and the sup pressed carrier wave of the transmitter is obtained in a simple manner.
  • auxiliary oscillations are sent out simultaneously with the on'e-s'ideband signal.
  • auxiliary oscillations are chosen in such manner that between the frequencies of these oscillations and of the suppressed carrier wave itself (or between the mutual differences of these frequencies respectively), there exist fixed ratios which are independent of the frequency variation of the transmitter.
  • auxiliary oscillations are transmitted simultaneously with the signal, the frequency of the one auxiliary oscillation being located at a determined distance (for example 1 l c./s. above and the frequency of the other auxiliary oscillation being located at a determined (for example equal) distance below the frequency band of the signal.
  • this correct position is obtained with the aid of oscillations generated by a control oscillator and by means of at least one frequencytransformation stage included in the receiving channel, the control oscillator being regulated dependently on the differential frequency of at least two auxiliary oscillations in such a manner that between the frequency of this oscillator and the said mutual frequency differences there always exist fixed ratios independent or substantially independent of the frequency variation of the receiver and the frequency of the oscillations with which the transformation is effected in the frequency-transformation stage, being regulated with the aid of or being determined by the frequency diiference between an oscillation derived from an auxiliary oscillation and an oscillation derived from the control oscillator.
  • the integral received signal inclusive of the two auxiliary oscillations may now be transformed in frequency, for example, in the receiver with the aid of a frequency f originating from'a (first) local auxiliary oscillator.
  • the frequency t is regulated dependently on the difference in frequenc between one of the auxiliary oscillations transformed in frequency, for example (f1+st) and a frequency originating from the control oscillator (for example f1), 1. e. dependently on the frequency difference (st).
  • the regulation of the frequency 15 may be effected, for example, in such a manner that the frequency difference (s-t) becomes equal to zero.
  • the frequency f3 derived from the control oscillator f3 may directly be used as a carrier wave for the demodulation of the signal.
  • the above-described method is not the only method which permits to obtain the carrier wave to be locally generated.
  • the aforesaid frequency transformation may be applied to 1'1 and is by mixing them with the frequency t and by regulating subsequently this frequency dependently on the difierence between the frequency (s+f1)the first auxiliary oscillation of the received signaland the frequency (t+,f1)the oscillation f1 transformed in frequency and derived from the control oscillator.
  • the frequency transformation is by mixing this frequency with the frequency difference 5 which exists between the first auxiliary oscillation (8+fl) and the frequency fl locally generated in the control oscillator; the frequency (8+J3) may be used in this case as the carrier wave.
  • a particular case presents itself if between the frequencies of the auxiliary oscillations and of the suppressed carrier wave itself there exist fixed ratios independent of the variation of the transmitter.
  • This case which ma be considered as a special form of realization of the above riescribed general case, may be realized, for example, by eifecting the frequenc transformation in the transmitter with the aid of a frequency s, which is derived from the common fundamental frequency f, i. e. by taking 8 equal to n). It is sometimes also possible to take 8 0 and directly to transmit the frequencies f1, f2 and the frequency band of the signal.
  • the frequency of the controloscillator may be regulated in such a manner that a fixed ratio will also be obtained between the said frequency and the frequency of the suppressed carrier wave.
  • a frequency transformat on stage in which the frequency transformation is effected by means of oscillations generated by a (first) local auxiliary oscillator it is possible to generate the carrier wave to be used for the detection with the aid of a (second) local auxiliary oscillator which operates independently of the control oscillator and which consequently is not controlled by the control oscillator.
  • the frequency of the first auxiliary oscillation must be regulated, in addition, dependently on the frequency of the second local auxiliary oscillation. This is efficiently effected by means of a frequency detector in which a voltage originating from at least one of the auxiliary oscillations of the signal is compared with a voltage which is derived both from the control oscillator and from the second local auxiliary oscillator.
  • the invention may also be applied in those cases in which more than one frequency transformation stage is used. If, in this case, a separate auxiliary oscillator is used in each stage, it suffices, as a rule, to regulate only one of these auxiliary oscillators in any of the above-mentioned ways.
  • Fig. 1 is a block diagram of the mixer and detector stages of a receiver according to the invention
  • Fig. 2 is a block diagram of another preferred embodiment of a receiver
  • Fig. 3 is a block diagram of still another preferred embodiment of a receiver
  • Fig. 4 is a block diagram of a transmitter arrangement according to the invention.
  • Fig. 5 is a block diagram of another transmitter arrangement according to the invention.
  • Fig. 1 represents diagrammatically the intermediate-frequency stage and the detection stage of a receiver suitable for the reception of onesideband signals with suppressed carrier wave, two auxiliary oscillations being transmitted simultaneously with these signals.
  • the frequencies of the two auxiliary oscillations and the frequency o the suppressed carrier wave are derived in a transmitter from a common fundamental frequency, so that monies we proceed as follows.
  • the local oscillations generated. in a local auxiliary oscillator 2v and serving for the frequency transformation are mixed in the intermediate-frequency stage i of the receiver with the received and, as the case may be, high-frequency-amplified signal. After being amplified, if required, the intermediate-frequency signal is supplied to three electric filters 3, i and 5.
  • the local oscillations generated. in a local auxiliary oscillator 2v and serving for the frequency transformation are mixed in the intermediate-frequency stage i of the receiver with the received and, as the case may be, high-frequency-amplified signal. After being amplified, if required, the intermediate-frequency signal is supplied to three electric filters 3, i and 5.
  • filter 3 allows only the frequency transformed.
  • auxiliary oscillations are supplied to a mixing stage 6, at whose terminals appears an oscillation whose frequency is equalto the difference between the frequencies of the two auxiliary oscillations. This oscillation is supplied to a frequency detector i.
  • an oscillator 8 (control oscillator) is generated an oscillation with the aid of which a multivibrator 9 is controlled.
  • This multivibrator generates the higher harmonics of the oscillation generated by the control oscillator.
  • One of these higher harmonics is now also supplied to the frequency detector 2 In choosing these higher har-
  • the frequencies of. the auxiliary oscillations (and. also the frequency of the suppressed carrier wave) of the signal are derived from a determined fundamental frequency 1".
  • the frequencies of the received auxiliary oscillations may consequently be represented by mi and mi respectively, whilst their difference is (n1n2)
  • the absolute values of the frequencies of the auxiliar oscillations have changed, it is true, but their difference has remained equal to (n1n2)f.
  • the frequency of the control oscillator 3 is made equal to f as exactly as possible and the (n1nz)th harmonic of this oscillator-which harmonic is generated by the multivibrator 9-is compared in the frequency detector 1 with the frequency difference of the auxiliary oscillations.
  • the frequency detector furnishes a control voltage which is dependent upon the difference in frequency between the two frequencies to be compared.
  • This control voltage controls a motor l0 which regulates the tuning frequency of the control oscillator. Owing to this regulation the frequency of the control oscillator is made equal, either exactly or within a very small amount, and also continuously kept equal to the fundamental frequency of the transmitter.
  • the suppressed carrier wave of the transmitter was a higher harmonic of this fundamental frequency; therefore, if at least no frequency transformation of the signal would have taken place, it would also be necessary to utilize in the receiver the corresponding higher harmonic of the control oscillator as the local carrier wave.
  • frequency transformation of the signal has taken place, it is, of course, also necessary to utilize a local carrier wave of other frequency.
  • a suitably chosen higher harmonic of the control oscillator 8 provided that the frequency of the local auxiliary oscillator 2 should satisfy a determined condition which will be set out hereinafter.
  • the frequency of the carrier wave not transformed in frequency may be represented by m where f designates again the fundamental frequency of the transmitter.
  • the suppressed, frequency-transformed carrier Wave amounts to (nzfit) and, as a rule, there does not exist a fixed ratio between this frequency and the frequency ,f of the control oscillator 8 or the frequency of any of the higher harmonics of this oscillator (which, in general can be represented by m
  • the auxiliary oscillator 2 is tuned as exactly as possible to a frequency which satisfies the said condition and then the correct value of this frequency is automatically adjusted with the aid of a motor l2 which is controlled by the output voltage of a frequency detector 53.
  • a frequency detector 53 two frequencies are compared with one another, viz. the frequency Of one of the frequency-transformed auxiliary oscillations and the frequency of that higher harmonic of the control oscillator which approaches nearest the first-mentioned frequency.
  • the frequency of the auxiliary oscillator 2 is adjusted in such a manner that the frequencies compared in the frequency detector I3 become equal or substantially equal to one another, that is to say that the frequency of one of the frequency-transformed auxiliary oscillations and therefore also the frequency of the suppressed, frequency-transformed carrier wave become equal to a harmonic of the control oscillator (i. e. to a multiple of the frequency 1), so that the condition to be fulfilled is complied with.
  • the local carrier wave which is now supplied by the multivibrator 9 as a higher harmonic of the control oscillator, is mixed in the detector H with the signal freed from the auxiliary oscillations by the filter 3, with the result that the signal is detected.
  • the low-frequency oscillations thus obtained are subsequently amplified in a low-frequency amplifier (not shown).
  • the demodulation frequencies of these channels may be derived from the control oscillator 8 or from the multivibrator at least if in the transmitter, the corresponding carrier waves of these channels are derived from the fundamental frequency of the transmitter.
  • Fig. 2 represents a receiver similar to that of Fig. 1. However, this receiver is suitable for the reception of one-sideband signals emitted by a transmitter, wherein the frequencies of the auxiliary oscillations and the frequency of the suppressed carrier wave are obtained by mean of a frequency transformation, from oscillations derived from one common fundamental frequency.
  • this fundamental frequency amounts to 1 kc./s., wherein the oscillations derived from this fundamental frequency have a frequency of 49, 48 and 27 kc./s.
  • the frequency of 48 kc./s. serves as the auxiliary carrier Wave and the two other frequencies serve for the derivation of the auxiliary oscillations.
  • the frequency band of the signal extends from 28 to 48 kc./s.; the whole of the signal is transmitted on short waves and is then received by the receiver.
  • the high-frequency signal is converted, as the case may be, after being amplified, in the usual manner into an intermediatefrequency signal (289-311 kc./s.).
  • the intermediate-frequency signal is mixed in the mixing stage I in the same manner as in the example according to Fig. 1, with the oscillations originating from the auxiliary oscillator 2.
  • the frequency of the auxiliary oscillator 2 is so chosen that th frequency-transformed signal extends again from 27 to 49 kc /s. (modulation width of the signal from 28 to 48 kc./s., frequency-transformed auxiliary oscillations 2'7 and 49 kc./s., frequency-transformed, suppressed carrier Wave 48 kc./s.).
  • the frequency-transformed signal is freed from the two auxiliar oscillations by two filters 3 and 3".
  • the filter 3' passes all oscillations having a frequency of less than 48 kc./s. and the filter 3 passes all frequencies having a frequency of more than 28 kc./s.
  • the signal is supplied to two filters i and i i; the filter 6 passes only the (first) auxiliary oscillation whose frequency is 49 l :c./sand the filter M passes all oscillations of the signal, except the first auxiliary oscillation.
  • the signal, in which the first auxiliary oscillation is suppressed by the filter Hi, is mixed in the mixing stage it with the 22nd harmonic of the control oscillator 8 (the frequency of the control oscillator is l kc./s.; the
  • the oscillations passed by the filters and 5 are compared with one another in the frequency detector 7.
  • the outward voltage of this frequency detector controls in its turn the motor l0 and the latter regulates the tuning frequency of the control oscillator 8 in such manner that the frequencies of the two oscilations supplied to the frequency detector are made equal to one another.
  • the frequency difference of the two auxiliary oscillations is made equal to a suitably chosen higher harmonic of the control oscillator 8,
  • the local carrier wave is not taken from the control oscillator, but is generated by a (second) local auxiliary osciilator I6 (48 kc./s.) which operates independently of this oscillator.
  • This auxiliary oscillator is introduced in order to be able to, avoid the generation of very high harmonics by the multivibrator 9.
  • the frequency of the first local auxiliary oscillator 2 should be regulated, in addition, dependently on the frequency of the second local auxiliary oscillator I6.
  • the oscillation generated by the auxiliary oscillator I6 (48 kc./s.) is mixed in a mixing stage I! with the frequency of the control oscillator 8 (l kc./s.).
  • the frequency of 49 kc./s. which appears after mixing is, supplied through a filter [8 which only passes this frequency, to the frequency detector I3 wherein it is compared with the first auxiliary oscillation 49 kc./s.
  • the frequency detector l3 regulates again in the previously described manner the tuning frequency of the auxiliary oscillator 2 through the intermediary of the motor I2.
  • the correct position of the locally generated carrier wave with respect to the frequency band of the received signal is thus ensured.
  • the detector II th local carrier wave is mixed with the signal freed from the. auxiliary oscillations, whereupon the developed low-frequency oscillations are transferred via a filter I9 which passes all oscillations of a frequency of less than 20 kc./s., to a low-frequency amplifier (not shown).
  • the amplification of the receiver may ad,- vantageously be automatically controlled dependently on the intensity with which at least two auxiliary oscillations are received.
  • the control voltage for the automatic control of the amplification may be generated with the aid of oscillations which the filters 4 and allow to pass.
  • the connecting terminals from which these oscillations may be taken are designated in the figure by 20.
  • Fig. 3 represents a receiver suitable for the reception of one-sideband signals with suppressed carrier wave, only one auxiliary; oscillation being transmitted simultaneously with the said signal.
  • the frequency of the auxiliary oscillation and the frequency of the suppressed carrier wave. are derived in the transmitter of these one-sideba ld Signals from a common fundamental frequency.
  • the circuit-arrangement corresponds, except in some details, with the circuit-arrangement shown in Fig. 1.
  • the auxiliary oscillation transformed in frequency is directly compared in the frequency detector '1 with an oscillation originating from the control oscillator 8, whilst in, the frequency detector I3.
  • the oscillation furnished by the local, auxiliary oscillator 2 is compared with a suitably chosen higher harmonic of the oscillation generated by the control oscillator 8.
  • the frequency detector [3 the frequency of the local auxiliary oscillation is made equal to the frequency of the said higher harmonic, so, that now there. exists, again a fixed ratio be,- tween the frequency of the, local auxiliary oscillation and the said common fundamental frequency.
  • the receiver according to Fig. 3 offers with respect to the receiver according to Fig. 2- the advantage of a considerably simplified c i-rc .uitarrangement but, on the other hand, it is not possible to switch over directly to any desired wave length.
  • the invention offers the advantage that the use of very stable oscillators is unnecessary and that upon modification of the frequency band 1d of. the signal only a small number of elements has to be exchanged.
  • a fundamental frequency generator 20 is provided to excite a harmonic generator 2
  • the carrier wave is modulated by the signal to be transmitted in a modulator 22 of any conventional design, and the modulated carrier as well as the first and second pilot oscillations are applied to a carrier suppression single side band system 223 so that but one sideband of the modulated carrier is transmitted in addition to the first and second pilot oscillations.
  • the invention is of particular importance for transportable transmitters an receivers.
  • mixer for applying oscillations from said local oscillator together with said incoming energy to said: mixer, a detector, means for applying the single side band signals component from the output of said mixer to said detector, a local carrier source, means for applying said local carrier to said detector to effect demodulation of said signals, and means responsive to the frequency of saidpilot oscillation to govern the frequency of said local oscillator to maintain the proper relation between the frequency of said local carrier and the side band signals componentv applied to said detector.
  • Apparatus for receiving incomin energy constituted by suppressed carrier single side band signals and first and second pilot oscillations, said suppressed carrier and said pilot oscillations being derived from a common wave source whereby fixed ratios exist between the respective frequencies of said carrier and said first and second oscillations relative to the frequency of said common source
  • said apparatus comprising a frequency mixer to produce intermediate frequencies, means to apply local oscillations and said incoming energy to said mixer, means to derive separately from said mixer the intermediate frequency components of said single side band signals and said first and second pilot oscillations, means to combine the intermediate frequency components of said first and second pilot oscillations to produce a beat oscillation, an adjustable control oscillator whose operating frequency is substantially equal to the frequency of said common wave source, harmonic producing means to derive from said control oscillator a carrier oscillation whose frequency is equal to the assumed intermediate frequency component of said suppressed carrier and a control oscillation whose frequency is equal to said beat oscillation, a detector, means to apply said carrier oscillation together with the intermediate frequency component of said
  • said means to govern the frequency of said control oscillator comprises a motor arranged for adjusting said oscillator, a frequency discriminator, means to apply said beat oscillation and said control oscillation to said discriminator to produce an error voltage in accordance with the frequency difference therebetween, and means to operate said motor in accordance with said error voltage.
  • harmonic producing means to derive from said control oscillator a local carrier whose frequency is equal to the assumed intermediate frequency component of said suppressed carrier and a first control oscillation whose frequency is equal to the intermediate frequency component of said first pilot oscillation and a second control oscillation whose frequency is equal to said beat oscillation, means to apply said local carrier together with the intermediate frequency component of said side band signals as an input to said detector to demodulate said signals, means to govern the frequency of said control oscillator as a function of the frequency difference between said beat and said second control oscillations, and means to control the frequency of said local oscillator as a function of the frequency difference between the intermediate frequency component of said first pilot oscillation and the first control oscillation.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
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US685122A 1943-10-21 1946-07-20 Transmitter and receiver for single-sideband signals Expired - Lifetime US2530614A (en)

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NL113583A NL78602C (en:Method) 1943-10-21 1943-10-21

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DE (1) DE932686C (en:Method)
FR (1) FR920008A (en:Method)
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NL (1) NL78602C (en:Method)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2622191A (en) * 1949-09-24 1952-12-16 Hartford Nat Bank & Trust Co Receiver circuit arrangement
US2699494A (en) * 1950-05-08 1955-01-11 Hartford Nat Bank & Trust Co Suppressed carrier single side band radio transmission system
US2724742A (en) * 1951-05-05 1955-11-22 Bell Telephone Labor Inc Suppressed-carrier amplitude modulation
US2777055A (en) * 1953-01-07 1957-01-08 Goldberg Bernard Automatic frequency control system with phase control for synchronous detection
US2855506A (en) * 1956-02-29 1958-10-07 Mackay Radio & Telegraph Co Automatic frequency control circuit for frequency shift radio telegraphy
US3017508A (en) * 1959-09-14 1962-01-16 Gen Electric Automatic gain control system
US3068416A (en) * 1957-02-07 1962-12-11 Sperry Rand Corp Communication system
US3088070A (en) * 1959-05-13 1963-04-30 Aeronautical Radio Inc Frequency correcting communication system and method
DE1196256B (de) * 1961-09-07 1965-07-08 Fuji Tsushinki Seizo Kabushiki Richtfunksystem mit Einseitenbandmodulation
US3320535A (en) * 1965-01-04 1967-05-16 Collins Radio Co Transmitted signal two tone difference controlled single sideband squelch and avc system
US3346860A (en) * 1964-02-20 1967-10-10 Int Standard Electric Corp Radio navigation system
US3364311A (en) * 1964-02-07 1968-01-16 Nasa Usa Elimination of frequency shift in a multiplex communication system
US3619782A (en) * 1966-01-28 1971-11-09 Hughes Aircraft Co Coherent catv transmission system
FR2382808A1 (fr) * 1977-03-03 1978-09-29 Licentia Gmbh Faisceau hertzien pour exploitation a bande laterale unique

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NL112309C (en:Method) * 1958-06-12
US3202765A (en) * 1961-08-23 1965-08-24 Bell Telephone Labor Inc Synchronization of frequency multiplex systems
US3196352A (en) * 1962-12-18 1965-07-20 Ibm Multilevel vestigial sideband suppressed carrier data transmission system
US3370235A (en) * 1964-09-11 1968-02-20 Nippon Electric Co Dual pilot frequency-correcting terminal stations for satellite repeater system
DE1286146B (de) * 1968-01-02 1969-01-02 Inst Rundfunktechnik Gmbh Empfaenger fuer amplitudenmodulierte Hochfrequenzschwingungen, insbesondere nach dem Einseitenbandverfahren ausgestrahlte Hochfrequenzschwingungen

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US2117752A (en) * 1936-05-05 1938-05-17 Bell Telephone Labor Inc Harmonic producer
US2129020A (en) * 1935-04-10 1938-09-06 Rca Corp Modulated carrier wave receiver
US2195485A (en) * 1939-05-04 1940-04-02 Peerless Machinery Co Pinking machine
US2273023A (en) * 1939-02-02 1942-02-17 Henri Jean Joseph Marie De De Radiotelephone system

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CH197737A (de) * 1936-07-20 1938-05-15 Licentia Gmbh Verfahren zur Synchronisierung der an beliebiger Stelle zugesetzten Trägerschwingung bei Sendungen mit unterdrückter Trägerfrequenz, insbesondere bei Einseitenbandsendungen.

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US1490958A (en) * 1924-04-22 Frequency-control system
US1694473A (en) * 1928-12-11 High-frequency signaling
US1449372A (en) * 1915-12-01 1923-03-27 Western Electric Co System of telephony
US1690299A (en) * 1922-03-21 1928-11-06 Western Electric Co Generation and control of electric waves
US1678203A (en) * 1923-02-27 1928-07-24 Western Electric Co Communicating and switching system
US1797976A (en) * 1926-07-09 1931-03-24 Gen Electric Fault-responsive apparatus
US1848507A (en) * 1928-10-08 1932-03-08 Signors to telefonaktobolaget l
US1885728A (en) * 1930-06-19 1932-11-01 Bell Telephone Labor Inc Harmonic generating and selecting system
CH182214A (de) * 1931-05-20 1936-01-31 Bell Telephone Mfg Einseitenband-Fernmeldeanlage.
US2129020A (en) * 1935-04-10 1938-09-06 Rca Corp Modulated carrier wave receiver
US2117752A (en) * 1936-05-05 1938-05-17 Bell Telephone Labor Inc Harmonic producer
US2094113A (en) * 1936-07-10 1937-09-28 American Telephone & Telegraph Wave transmission
GB480847A (en) * 1936-07-20 1938-03-01 Telefunken Gmbh Improvements in or relating to suppressed carrier wave signalling systems
US2105809A (en) * 1936-08-01 1938-01-18 Wired Radio Inc Carrier supply system
US2273023A (en) * 1939-02-02 1942-02-17 Henri Jean Joseph Marie De De Radiotelephone system
US2195485A (en) * 1939-05-04 1940-04-02 Peerless Machinery Co Pinking machine

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2622191A (en) * 1949-09-24 1952-12-16 Hartford Nat Bank & Trust Co Receiver circuit arrangement
US2699494A (en) * 1950-05-08 1955-01-11 Hartford Nat Bank & Trust Co Suppressed carrier single side band radio transmission system
US2724742A (en) * 1951-05-05 1955-11-22 Bell Telephone Labor Inc Suppressed-carrier amplitude modulation
US2777055A (en) * 1953-01-07 1957-01-08 Goldberg Bernard Automatic frequency control system with phase control for synchronous detection
US2855506A (en) * 1956-02-29 1958-10-07 Mackay Radio & Telegraph Co Automatic frequency control circuit for frequency shift radio telegraphy
US3068416A (en) * 1957-02-07 1962-12-11 Sperry Rand Corp Communication system
US3088070A (en) * 1959-05-13 1963-04-30 Aeronautical Radio Inc Frequency correcting communication system and method
US3017508A (en) * 1959-09-14 1962-01-16 Gen Electric Automatic gain control system
DE1196256B (de) * 1961-09-07 1965-07-08 Fuji Tsushinki Seizo Kabushiki Richtfunksystem mit Einseitenbandmodulation
US3364311A (en) * 1964-02-07 1968-01-16 Nasa Usa Elimination of frequency shift in a multiplex communication system
US3346860A (en) * 1964-02-20 1967-10-10 Int Standard Electric Corp Radio navigation system
US3320535A (en) * 1965-01-04 1967-05-16 Collins Radio Co Transmitted signal two tone difference controlled single sideband squelch and avc system
US3619782A (en) * 1966-01-28 1971-11-09 Hughes Aircraft Co Coherent catv transmission system
FR2382808A1 (fr) * 1977-03-03 1978-09-29 Licentia Gmbh Faisceau hertzien pour exploitation a bande laterale unique
US4209748A (en) * 1977-03-03 1980-06-24 Licentia Patent-Verwaltungs-G.M.B.H. Directional radio system for single sideband operation

Also Published As

Publication number Publication date
FR920008A (fr) 1947-03-25
GB636467A (en) 1950-05-03
NL78602C (en:Method) 1955-06-22
DE932686C (de) 1955-09-05

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